The Inhibitory Effect Of Chlorin E6-mediated Photodynamic Therapy On A Human Cholangiocarcinoma Cell Line QBC939in Vitro

Background and aims:The poor prognosis of cholangiocarcinoma(CCA), is not sensitive to chemotherapy and radiotherapy. Photodynamic therapy (PDT) has achieved initial success in CCA treatment abroad.This part of the study was to investigate the killing effect of chlorin e6-mediated photodynamic therapy (Ce6-PDT) on human CCA cell lineQBC939in vitro.Methods:The QBC939cells were divided into four groups:control, photoradiation only, chlorin e6only and chlorin e6-mediated photoradiation. CCK-8assay was used to determine the cell viability of QBC939. ROS generation by Ce6-PDT was measured by the DCFH-DA method. Cell Death Detection enzyme-linked immunosorbent assay (ELISA) plus assay was performed to detect the killing effect of PDT on QBC939cells. FITC-annexin V and PI were used to identify apoptosis of QBC939cells.Results:The growth of QBC939cells in the chlorin e6-mediated photoradiation group were inhibited significantly compared to the other groups (p<0.05). NO significance was detected when cells received the same concentration of chlorin e6, different intensity of photoradiation. While, the production of ROS, cell death and apoptosis were elevated along with the increase in the concentration of cholorin e6when the cells received the same intensity of photoradiation.Conclusion:The chlorin e6-mediated photodynamic therapy has significant killing and inhibitory effect on human cholangiocarcinoma cells, and the effect appears to be correlated with the dose of chlorin e6. Background and aims:Cholangiocarcinoma cells can autocrine IL-6which can maintain activation of STAT3. The Bcl-2/Bax proteins were downstream of STAT3signaling pathway, and play an important role in the regulation of apoptosis of tumor cells. The effect of photodynamic therapy on cholangiocarcinoma cells autocrine IL-6is still not clear. In our study, we will investigate the influence of expression of IL6/STAT3and Bcl-2/Bax by Chlorin e6-mediated photodynamic therapy.Methods:1) QBC939cells were treated by photodynamic treatment as shown in the first part of such papers.2) Human IL-6Detection ELISA was used to evaluate level of IL-6in the culture supernatant;3) Western Blotting were employed to test STAT3, p-STAT3, Bcl-2and Bax protein expression of QBC939cell by Chlorin e6-mediated photodynamic therapy.Results:In the photodynamic therapy group, with the increment of the the photodynamic parameter values, IL-6production in the QBC939cells was increased after24h by PDT. PDT significantly inhibited the expression of STAT3, p-STAT3. The anti-apoptotic protein Bcl-2was down-regulated, while Bax was increased.Conclusions:IL-6content presented in ascending order in QBC939cells supernatant after PDT. Ce6-PDT suppressed the expression of STAT3, p-STAT3and its anti-apoptotic protein Bcl-2expression, while thepro-apoptotic protein Bax was increased.